Method of making seal members



J 1945- c. v. LITTON 2379,584 I METHOD OF MAKING SEAL MEMBERS Filed Jan.31, 1942 2 Sheets-Sheet l F'IG.2.

IN VEN T OR. CHARLES l4 L/TTO/V A TTORA E Y.

Patented July 3, 1945 4 H $379,584 Mamet.osMA sEAtMEMissRs Charles-V.Litton, Redwood City; Calif.; assigno'r toolntemational StandardElectric Corporation,

a I New .Yorlt-,N'.Y.',acorporation Delaware 1 1 s mieatitaismms miasiatno. 429,013.

Claims. (Cl. 29-51484 j wh n has o me h d o makin metallic seal m m rsof a. t pe u e n la o-hie else ls of vacuum, tubes 'lihe oh'e is to pr vde a imp e method fo iebticatm e meta membexs; i he e le wi h asheewhieh i w ll sui difer seali gw th glass toiolmast one seal,

. :In theme u a ure of. v cu m. tu es' hic the. wheel emposed o m tallta i ns in dditiqn, to. vitreous. or; glass sections, the vitreous sectons. a e se le t he etal se iohsf is well known, forming a vacuum tightjoint, In

omen to-mihimiae thedanser. of heckin f t glass owing to thermal changescare mustfbe taltenutol form. th metal emb r o. that he st ai s. a einim zed.- orl h s p rpose, it h been ustomar to mioi ide th m tal m mbwith thihfiahsest ieh. h s s'se s to be s a d.

so; thatwh h the l ss, tr ets, the h n fla ge a ath so. as o l a ethedesired. thin fo teeth:

he! hes he. disadvanta e of being v rylabor ous Y and expensive, and isnot especially Well. a lahted,

to fo min hesea e e in o e pe ally desir l shame In aoco ahee wi h thisinyention t e e is. need; a. rolli g pro e which, does not. requi e yturning. A laminar a n us s s eared alone. the e ge. of a. m ta ic di csha ed. blank a tllmed over, so. hat. t xten s subs n a ly prhehdiehlany. f om the. side o v he an d t e tiirlnesi over a nation. ist en rolle do n. nto a da hed hane, T is v i s a y equ remen o turnin heme al andhas t dv n a e offer tin fine... r st l in S ture y the cold.

t lling process. so that th ge port o s. o th eali flanees. are madeespecially imper iqhs o gas. 4

lowing detailed description taken in connection with the accompanyingdrawing, ofwhich isaside View of, a blank disc which is to 'I he processwill be understood from the fol- I hel' abi ated into a se l; m m e inco dan e with hisih en i n Fig.2 is a cgbss section VleW Of the blank,taken at line 5- iEi 1v; 1

i l stra es. a steo o hea i amina ehhhls. a e hhi aoe o h blanket F s 1R se nd; .5 illust a es-th a tejhinad wn. o the laminations formedaccording to Fig. 3;

6-showsthesteghi rolling out the laminations which have been flattenedas shown in Fig.

5; and

; This an n arge sect on l V ew eta seal memb ro l d-in o a eci lhane'anci seale to las s ctions i I l E s na hew 'a isc l, hieh maylbe.- oi opper, hav g; a ho e. ri led,v ce a ly through o th ameter h h iis iht i ec'tv the hhe m s sur aeeo eal memb rsha ha e... The two. 69 3;and, v nd a so-the, surface 0; the le a eh derabh machi ed- The d sh mspl oed o mandhel mem 6, with mem ntos he man r l ht eh he ho e Lena a.coon ate ihgm n l m m er-1 is rou h up agmhstthe op o te fa e of the. dit. s h tv he; disei firmly. held between the. faces 8F and .9 of. the.mandrels, Mandrel 1; is ho11owed,-out to form. a oax a cylind intow chhe ylihdrieal meek. 5 fits. 'Ifhemandrel members-'6 ands ,1 are, earnedlay-the; 1 theitailshaits u and limiting conical p in 3;- and M ect y ih fit into. cort spomiine onical e-entrant portions. of. the. manqre tMemb r. o. s t e o l r fastened. o andr l embert or p yi g thed y nstorque. of the, lathe in a well -k'nown manner. Laminar annuli l5 and,liiare then sheared; r. split along the faces 3 of the disc asillustrated in Fig,

4. This may be done in one ope qation by. the use of a splitting toolwhich may consistof, av pain. of ha dene nd; round steel rolle s. i1- q.t8. Ei h v g; sharp, ape utti ed es l9 and 2.0 r p cti ely; This. pairof Quilting rollers may be mounted. in .a well khowh manner on thegtoolpost of: the a he and adj d sothat. t e

2,2 of mecutting. portion 3. 1 alineq with each other andv parallel withthe disc snrf J3 and alo whiohthe amin tion. is to he s Theaxes Z3. and;2.4. of the cutting rollers may be laced at an an le of about. 4. de eto give desired adjustment of the facesZl and.22.' Thus, when the latheshafts Ii and, I2 are rotated to rotate the disc I, the cutting edgespressingagainst t e disc split th aminat ns and It. (Bi 4) almost downtothe. outside diameter of, mandrels 6 and].

T e am a ons, .v nd re n t n s me hat fla tened downo i t mandrel rfacesasmuch as possible, as shown in Fig. 5; andare rolled as shown in Fig. 6by means. of rollers 25. and 26 which may be placed in the tool post. Byreason of this rolling, the length of the lanai;- nation, or sleeve, isextended and should be ta: pe d s mewha n the form o Z and, 8 (Fig- Anydesired iormation or degree oftapercan be provided by manipulation anduse of the rollers, and. there is. thu fo d a al embe of a o m shown'inFig. 7, having a strong centfal; portion 29 and relatively longcylindrical" collarmembers- 30 and. 3|, which taper down to a thin areaadare especially advantageous are described and;

2,379,584 j 3 if claimed in my copending application Ser. No. 7,

429,072, filed January 31, 1942, now Patent No.

2,336,488. A cylindrical glass section may then be sealed to collarmember 30 and another glass section 35 may be sealed to the collarmember 3| in a well-known manner. A

The cold rolling of the split- 011 sleeves or collar members 30 and 3|has the great advantage over the laborious alternative process ofturning down a massive cylinder to the same shape, of saving the largemass of the metal which would otherwise become waste by the turning, andof eliminating the corresponding heavy wear on the turning tool. Thecold rolling has the further greatadvantage over a turning process ofbreaking down the-crystal sizes in the sleeve, which is a greatadvantage in vacuum tube seals. Copper blanks to be made into seals arecustomarily annealed before being fabricated into the seals, and

the annealing process produces large crystals which might very Wellextend all the way across the thickness of the thin sleeves 30 and 3!.Gas seepage might consequently occur past the cleav-' ages of such largecrystals which would deleteriously affect thevacuum tube operation. Thecold rolling of the sleeves breaks down such large crystals into muchsmaller crystals, such that gas seepage through the sleeve does notoccur. The crystal size should be no greater than one-half the thicknessof the sleeve, andis preferably of the order of one-tenth or even less,of the sleeve thickness. Such a fine crystalline structure is providedby the cold rolling which can'produce crystals of the order of .0025 to.0035 millimeter in diameter or length.

What is claimed is:

1. Themethod of making a seal member which comprises binding a metallicdisc having a centrally located hole therein, between two mandrelmembers having cylindrical outer surfaces of a diameter greater thanthat of said hole and less than the outside diameter of said disc,shearing a lamination parallel to a face of the disc, from the outsidecircumference of the disc, down substantially to the diameter of saidmandrel, turning over the sheared lamination on to the mandrel, and thenrolling the turned over lamination on the circumference of the mandrelto form a tapered margin.

'2. The method of making a seal member which comprises binding ametallic disc having a central hole therein, between two mandrel membershaving cylindrical outer surfaces of a diameter greater than that ofsaid hole and less than the outside diameter of said disc, shearing alaminaill ing rolling pressure to the outer 3. The method of making aseal member useful for vacuum tubes which comprises making a holethrough a disc, shearing a lamination from the outer circumference partWay to the hole, turning over the sheared lamination against a mandrel,and then rolling the turned over lamination between a mandrel member anda rollingtool to form a sleeve extending, from the body of the disc andto reduce by said rolling operation the sizes of the crystal in thesleeve to less than one-half the sleeve thickness.

4. The method of making a substantially symmetricaltubular sealhaving athick mid section and relatively thin tubular end portions suitable forforming gas-tight sealed connections to two tubular vitreous portions ofa vacuum tube envelope, which comprises securing a metallic disc havinga. central hole therein between two coaxial mandrel members havingcylindrical outer surfaces of a diameter greater than that of said holeand less than'the outside diameter of said disc, shearing flanges fromsaid disc near opposite faces thereof from the outside circumference ofthe disc down substantially to the diameter of the respective mandrelmembers, then turning the flanges over on saidmandrel members, andthereafter forming said flanges into tapered tubular sleeves having thinouter'margins suitable ior said seal connection by applysurfaces of theflanges.

5. The method set forth in claim 4, the flanges are shearedsimultaneously.

6. The method of making a seal member having a tapered margin suitablefor sealing to a vitreous portion of a vacuum tube envelope whichcomprises mounting a disk having a central hole on a mandrel having asubstantially cylindrical face adjacent one side of the disk, cutting aradial annular incision in the disk to form an annular flange at saidside, forcing the flange against the mandrel to form a substantiallycylindrical sleeve, and tapering the sleeve to a thin edge suitable forhermetic sealing to said vitreous portion by applying rolling pressureto the sleeve against the mandrel.

7. The method set forth in claim 6, in which r the rolling pressure isapplied by rolling means traveling circumferentially sleeveand themandrel axis.

8. The method set forth in claim 6, in which the disk is formed of ametal having crystals around the tubular whose maximum dimensions aresubstantially tion parallel to a face of the disc, from the outgreaterthan half of the desired thickness of the outer marginal portion of thesleeve and .the roll-' ing pressure is maintained until said crystalsare reformed into relatively small crystals having maximum dimensionssubstantially less than half of the thickness of the outer marginalportion of the sleeve.

9. The method set forth in claim 6, in which the outer edge ofthe sleeveis cut off at'an'angle of about 45 degrees.

10. The method of making a seal member usefulfor vacuum tubes whichcomprises making a hole through a disc, shearing a lamination from theouter circumference part way to the hole,

5 turning over the sheared lamination against a mandrel, and thenrolling between a mandrel member and a rolling tool the turnedoverlamination by substantial radial pressure to form a sleeve oftapered thickness extending from the body of the disc.

. CHARLES V. LI'ITON.

in which

